Molecular Analysis of an EL4 Cell Line That Expresses H-2Dbbut not H-2Kbor β2-microglobulin

EL4/Mar is a variant cell line that expresses H-2Dbbut neither H-2Kbnor β2-microglobulin (β2m). Southern and RNA blot analysis and immunoprecipitation of metabolically labeled proteins established that the B2m gene(s), β2m mRNA, and β2m protein are normal in this cell line. Somatic cell hybridization showed that the defect in this cell line was in the synthesis of H-2Kb, and RNA blot analysis with an H-2Kbspecific oligonucleotide established that the H-2Kbgene(s) in this cell line was not transcribed into a stable mRNA species. The apparent absence of β2m on the surface of this cell line suggests that there may be some feature of the H-2Dbmolecule that allows it to be expressed in the absence of detectable β2m.